feat(backgrounds): add liquid-gradient background

src/locales/en.json

@@ -1161,6 +1161,8 @@
       "starfieldDesc": "Stars flying toward the viewer",
       "matrixRain": "Matrix Rain",
       "matrixRainDesc": "Falling columns of glyphs",
+      "liquidGradient": "Liquid Gradient",
+      "liquidGradientDesc": "Blurred mesh gradient blobs",
       "geminiEffect": "Gemini Effect",
       "geminiEffectDesc": "SVG effect like Google Gemini",
       "speed": "Speed",

src/locales/fa.json

@@ -1043,6 +1043,8 @@
       "starfieldDesc": "پرواز در میان ستاره‌ها",
       "matrixRain": "باران ماتریکس",
       "matrixRainDesc": "ستون‌های نمادهای در حال سقوط",
+      "liquidGradient": "گرادیان مایع",
+      "liquidGradientDesc": "حباب‌های گرادیان مات و روان",
       "geminiEffect": "افکت Gemini",
       "geminiEffectDesc": "افکت SVG مشابه Google Gemini",
       "speed": "سرعت",

src/locales/ru.json

@@ -1191,6 +1191,8 @@
       "starfieldDesc": "Полёт сквозь звёздное небо",
       "matrixRain": "Matrix Rain",
       "matrixRainDesc": "Падающие колонки символов",
+      "liquidGradient": "Liquid Gradient",
+      "liquidGradientDesc": "Жидкий mesh-градиент из размытых блобов",
       "geminiEffect": "Gemini Effect",
       "geminiEffectDesc": "SVG-эффект как на Google Gemini",
       "speed": "Скорость",

src/locales/zh.json

@@ -1043,6 +1043,8 @@
       "starfieldDesc": "向观察者飞来的星星",
       "matrixRain": "黑客帝国雨",
       "matrixRainDesc": "下落的字符列",
+      "liquidGradient": "流体渐变",
+      "liquidGradientDesc": "模糊的网格渐变色块",
       "geminiEffect": "Gemini效果",
       "geminiEffectDesc": "类似Google Gemini的SVG效果",
       "speed": "速度",